Misalignment detection devices

ABSTRACT

A misalignment detection device comprising a substrate, at least one integrated circuit (IC), and at least one detection unit is disclosed. The substrate comprises a first positioning pad and a second positioning pad adjacent to the first positioning pad. The integrated circuit is disposed on the substrate and comprises a first positioning bump and a second positioning bump adjacent to the first positioning bump. The first and second positioning bumps substantially correspond to the first and second positioning pads, respectively. The at least one detection unit is electrically coupled to the substrate, wherein the detection unit outputs a fault signal in response to a positioning shift occurring between the first and second positioning pads and the first and second positioning bumps.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a division of U.S. patent application Ser. No.11/535,141, filed Sep. 26, 2006, and entitled “Misalignment DetectionDevices,” which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a misalignment detection device, andmore particularly, to a misalignment detection device applied inpressure exerted on an integrated circuit and at least one substrates.

2. Description of the Related Art

In nowadays electronic devices, elements are connected to a majorcircuit through conductive films, such as anisotropic conductive films(ACFs), which are formed by mixing non-conductive resins and conductiveparticles. FIG. 1A is a cross-sectional view of a conductive particle 1.The diameter of the conductive particle 1 is about 3 μm to about 5 μm.The center portion 1 a of the conductive particle 1 is formed by apolymer, and the conductive particle 1 is covered externally by a metalconductor 1 b, such as gold, silver, nickel, tin, copper, or the like.

ACFs are typically used for the manufacture of displays. In amanufacturing method, an ACF is used to directly dispose the drivingchips of a panel on a glass substrate, known as the Chip-On-Glass (COG)procedure or an ACF is used to dispose the driving chips on a flexibleprinted circuit (FPC), known as the Chip-On-Film (COF) afterward the FPCis electrically coupled to a substrate. In addition, an ACF is used todispose the driving chips on a printed circuit board (PCB), known as theChip-On-Board (COB).

FIG. 1B shows pressure between a substrate and a driving chip through anACF. Referring to FIG. 1B, a substrate 10 can be a glass substrate, anFPC, a PCB, or other circuit boards. During manufacture, metal pads 10 aare formed on the substrate 10 to transmit signals or power, such asvoltage level, current, or likes. Thick bumps 11 a are formed on pins ofthe driving chip 11. An ACF 12 is then disposed between the driving chip11 and the substrate 10. ACF 12 is heated to increase adhesioncapability, and then applying a pressure on the driving chip 11 and thesubstrate 10 so as to assembly. Note that the pads 10 a and thecorresponding bumps 11 a must be aligned.

Since each bump 11 a has a fixed thickness, conductive particles 1 arecompressed between the pads 10 a and the bumps 11 a. Through metalconductors 1 b externally covering the conductive particles 1, thecompressed conductive particles 1 electrically connected to the bumps 11a and the pads 10 a. Thus, the motion of the driving chip 11 and thecoupling of circuits are performed at the same time by ACFs.

During manufacture, the accuracy of disposition alignment is determinedby the naked eye of the operator, thus, a great number of detectionoperators is required. Moreover, the accuracy of disposition alignmentmay be suffered due to erroneous detection by operators or aninsufficient sampling rate.

As shown in FIG. 2A, the misalignment occurs between the bump 11 a ofthe driving chip 11 and the pad 10 a of the substrate 10. The bump 11 ais electrically connected to a pad adjacent to the corresponding pad 10a, and the misalignment thus occurs. In another case as shown in FIG.2B, although the bump 11 a is not electrically connected to the nextpad, a short path is formed between the bump 11 a and the pad adjacentto the corresponding pad 10 a via the conductive particle 1. Iferroneous or incomplete detection occurred by the operators leading toproduce the defective products.

BRIEF SUMMARY OF THE INVENTION

Misalignment detection devices are provided. An exemplary embodiment ofa misalignment detection device comprises a substrate, at least oneintegrated circuit (IC), and at least one detection unit. The substratecomprises a first positioning pad and a second positioning pad adjacentto the first positioning pad. The integrated circuit is disposed on thesubstrate and comprises a first positioning bump and a secondpositioning bump adjacent to the first positioning bump. The first andsecond positioning bumps substantially correspond to the first andsecond positioning pads, respectively. The at least one detection unitis electrically coupled to the substrate, wherein The detection unitoutputs a fault signal in response to a positioning shift occurringbetween the first and second positioning pads and the first and secondpositioning bumps.

A detailed description is given in the following embodiments withreference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from thedetailed description given hereinbelow and the accompanying drawings,given by way of illustration only and thus not intended to be limitativeof the present invention.

FIG. 1A is a cross-sectional view of a conductive particle of an ACF;

FIG. 1B shows pressure between a substrate and a driving chip through anACF;

FIG. 2A shows misalignment occurring between a driving chip and asubstrate;

FIG. 2B shows a short path formed by conductive particles of an ACF;

FIG. 3A shows a first embodiment of a misalignment detection device ofthe present invention;

FIG. 3B shows misalignment occurring in the embodiment of themisalignment detection device of FIG. 3A.

FIG. 4 shows a short path formed by conductive particles of an ACF in anembodiment of a misalignment detection device;

FIG. 5 shows distances between positioning pads and between functionpads in an embodiment of a misalignment detection device of the presentinvention;

FIG. 6A shows a second embodiment of a misalignment detection device ofthe invention;

FIG. 6B is a cross-sectional view of the exemplary embodiment of themisalignment detection device in FIG. 6A; and

FIG. 7 shows a third embodiment of a misalignment detection device ofthe present invention.

DETAILED DESCRIPTION OF THE INVENTION

The following description is of the preferred embodiments of carryingout the present invention. This description is made for the purpose ofillustrating the general principles of the present invention and shouldnot be taken in a limiting sense. The scope of the present invention isbest determined by reference to the appended claims.

Misalignment detection devices are provided. In a first embodiment of amisalignment detection device in FIG. 3A of the present invention, amisalignment detection device 3 comprises a substrate 30, at least oneintegrated circuit (IC) 31, and at least one detection unit 32. Inpresent embodiment of the invention, the substrate 30 can be atransparent substrate (such as a glass substrate, or a quartzsubstrate), an opaque substrate (such as a wafer or ceramic substrate),or flexibility substrate (such as acrylic polymer, rubber, epoxypolymer, ester polymer, or likes). In the following description of FIG.3A, a glass substrate is given as an example for the substrate 30, butnon-limited it. Referring to FIG. 3A, the substrate 30 comprises aplurality of pads divided into function pads 30 c and two adjacentpositioning pads 30 a and 30 b. The distance between any two of thefunction pads 30 c is substantially greater than the distance between ofthe positioning pads 30 a and 30 b. The IC 31 comprises a plurality ofbumps divided into function bumps 31 c and two adjacent positioningbumps 31 a and 31 b. An ACF 33 is disposed between the substrate 30 andthe IC 31. The ACF 33 is heated to increase adhesion capability, andthen applying a pressure on the substrate 30 and the IC 31. Preferably,the function pads 30 c and the substantially corresponding functionbumps 31 c should be aligned, and the positioning pads 30 a and 30 b andthe substantially corresponding position bumps 31 a and 31 b should bealigned.

In the present embodiment of the invention, the positioning pads 30 aand 30 b receive signals S30 a and S30 b having substantially differentvoltage levels, respectively. When the misalignment detection device 3is applied in a display device, at least one of the signals S30 a andS30 b is disregards display device functions. In other words, at leastone of the signals S30 a and S30 b is not provided by the displaydevice. For example, the signal S30 a has the same level as a commonvoltage Vcom of the display device, and the signal S30 b has a groundlevel GND provided by the misalignment detection device 3 or an externaldevice (not shown).

The detection unit 32 is electrically coupled to the substrate 30 anddetects the signals S30 a and S30 b. As shown in FIG. 3B, when thepositioning shift occurs between the substrate 30 and the IC 31, thedetection unit 32 outputs a fault signal S32. In detail, when thepositioning shift occurs between the substrate 30 and the IC 31 and themisalignment is caused between the function pads 30 c and the functionbumps 31 c, the positioning pad 30 a is electrically coupled to thepositioning bump 31 b or the positioning pad 30 b is electricallycoupled to the positioning bump 31 a, at the same time, one function pad30 c is electrically coupled to a function bump adjacent to thesubstantially corresponding function bump 31 c. One of the signals S30 aand S30 b is not at the original voltage level. When detecting that thevoltage level of one of the signals S30 a and S30 b is changed, thedetection unit 32 outputs the fault signal S32 to indicate a positioningshift between the substrate 30 and the IC 31. The display devicedisplays images incorrectly according to the fault signal S32, and thedisposition of the substrate 30 and the IC 31 faults.

In the present embodiment of the invention, the distance between twofunction pads 30 c is substantially greater than the distance betweenthe positioning pads 30 a and 30 b. When the positioning shift occursbetween the substrate 30 and the IC31, the positioning pad 30 a has beenelectrically coupled to the positioning bump 31 b or the positioning pad30 b has been electrically coupled to the positioning bump 31 a,notwithstanding any one of the function pads 30 c may not yet beelectrically coupled to a function bump adjacent to the substantiallycorresponding function bump 31 c causing the misalignment. Thus, thepositioning shift between the substrate 30 and the IC 31 can bedetermined in advance, decreasing the probability of the misalignment.

In FIG. 3A, the distance between two function pads 30 c is substantiallygreater than the distance between the positioning pads 30 a and 30 b. Insome cases, although the positioning shift does not occur between thesubstrate 30 and the IC 31, the conductive particles of the ACF 33 forma short path between the positioning bumps and the positioning pads dueto the shorter distance between the positioning pads 30 a and 30 b, asshown in FIG. 4. In order to prevent the short path formed by theconductive particles of the ACF 33, the forms of the positioning pads 30a and 30 b can be made as shown in FIG. 5. In FIG. 5, the positioningpad 30 a comprising two portions 50 a and 50 b, and the positioning pad31 a comprising two portions 51 a and 51 b. The distance between thepositioning pads 30 a and 30 b has the maximum length Lmax and theminimum length Lmin. It is assumed that the distance between twofunction pads 30 c is about 20 um, the maximum length Lmax issubstantially equal to 20 um, and the minimum length Lmin issubstantially less than 20 um. Thus, when the positioning shift occursbetween the substrate 30 and the IC 31 and the misalignment has not yetbeen caused between the function pads 30 c and the function bumps 31 c,the positioning pad 30 a has been electrically coupled to thepositioning bump 31 b or the positioning pad 30 b is coupled to thepositioning bump 31 a, thereby the positioning shift between thesubstrate 30 and the IC 31 can be known in advance. Moreover, becausethe distance between the portions 50 b and 51 b of the positioning pads30 a and 30 b is less than bout 20 um, the short path formed by theconductive particles of the ACF 33 can be prevented.

In the present embodiments of the invention, the positioning bumps 31 aand 31 b are disposed on an outer side of the IC 31, in other words, thepositioning bumps 31 a and 31 b are disposed on one of the two sides ofthe function bumps 31 c.

In a second embodiment of a misalignment detection device in FIG. 6A ofthe present invention, a misalignment detection device 6 comprises afirst substrate 60, a second substrate 61, and at least one detectionunit 62. The second substrate 61 is electrically coupled to and disposedon partly of the first substrate 60. The first substrate 60 can be aprinted circuit board (PCB), a flexible printed circuit (FPC), COF, or acombination thereof. The second substrate 61 can be a PCB, an FPC, or acombination thereof. In present embodiment of the invention, the firstsubstrate 60 is a PCB, and the second substrate 61 is an FPC is given asan example, but non-limited it. Referring to FIG. 6A, the firstsubstrate 60 comprises a plurality of electrodes divided into functionelectrodes 60 c and two adjacent positioning electrodes 60 a and 60 b,and the second substrate 61 comprises a plurality of electrodes dividedinto function electrodes 61 c and two adjacent positioning electrodes 61a and 61 b. Referring to FIG. 6 b, an ACF 63 is disposed between thefirst substrate 60 and the second substrate 61. The ACF 63 is heated toincrease adhesion capability, and then applying a pressure on the firstsubstrate 60 and the second substrate 61. Preferably, the functionelectrodes 60 c of the first substrate 60 and the function electrodes 61c of the first substrate 60 should be aligned, and the positioningelectrodes 60 a and 60 b of the first substrate 60 and the positioningelectrodes 61 a and 61 b of the first substrate 60 should be aligned.

In the present embodiment of the invention, at least one of the distancebetween two of the function electrodes 60 c of the first substrate 60 issubstantially greater than the distance between the positioningelectrodes 60 a and 60 b or the distance between two function electrodes61 c of the second substrate 61 is substantially greater than thedistance between the positioning electrodes 61 a and 61 b. In thefollowing description, the distance between two function electrodes 60 cof the first substrate 60 is substantially greater than the distancebetween the positioning electrodes 60 a and 60 c.

The positioning electrodes 60 a and 60 b respectively receives signalsS60 a and S60 b which have substantially different voltage levels. Whenthe misalignment detection device 6 is applied in a display device. Atleast one of the signals S60 a and S60 b disregards display devicefunction. In other words, at least one of the signals S60 a and S60 b isnot provided by the display device. For example, the signal S60 a hasthe same level as a common voltage Vcom of the display device, and thesignal S60 b has a ground level GND provided by the misalignmentdetection device 6 or an external device (not shown).

The detection unit 62 is electrically coupled to or disposed on thefirst substrate 60. The detection unit 62 detects the signals S60 a andS60 b. When a positioning shift occurs between the first substrate 60and the second substrate 61, the detection unit 62 outputs a faultsignal S62. In detail, when the positioning shift occurs and themisalignment is thus caused between the function electrodes 60 c and thefunction electrodes 61 c, the positioning electrode 60 a is electricallycoupled to the positioning electrode 61 b or the positioning electrode60 b is electrically coupled to the positioning electrode 61 a, at thesame time, one function electrode 60 c of the first substrate 60 iselectrically coupled to a function electrode adjacent to thesubstantially corresponding function electrode 61 c of the secondsubstrate 61. One of the signals S60 a and S60 b is not at the originalvoltage level. When detecting that the voltage level of one of thesignals S60 a and S60 b is changed, the detection unit 62 outputs thefault signal S62 to indicate the positioning shift occurs between thefirst substrate 60 and the second substrate 61.

In the present embodiment, the distance between two function electrodes60 c of the first substrate 60 is substantially greater than thedistance between the positioning electrodes 60 a and 60 b thereof. Whenthe positioning shift occurs between the first substrate 60 and thesecond substrate 61, the positioning electrode 60 a has beenelectrically coupled to the positioning electrode 61 b or thepositioning electrode 60 b has been electrically coupled to thepositioning electrode 61 a although any one of the function electrodes60 c of the first substrate 60 is not yet electrically coupled to afunction electrode adjacent to the substantially corresponding functionelectrode 61 c of the second substrate 61 causing misalignment. Thus,the positioning shift between the first substrate 60 and the secondsubstrate 61 can be known in advance, decreasing the probability of themisalignment.

In FIG. 6A, the distance between two function electrodes 60 c issubstantially greater than the distance between the positioningelectrodes 60 a and 60 b. In some cases, although the positioning shiftdoes not occur between the first substrate 60 and the second substrate61, the conductive particles of the ACF 63 form a short path between thepositioning electrodes 60 a and 60 b and the positioning electrodes 61 aand 61 b due the shorter distance between the positioning electrodes 60a and 60 b. In order to prevent the short path formed by the conductiveparticles of the ACF 63, the positioning electrodes 60 a and 60 b can beformed as shown in FIG. 5. The distance between the positioningelectrodes 60 a and 60 b has the maximum length Lmax and the minimumlength Lmin. It is assumed that the distance between two functionelectrodes 60 c is about 20 um, the maximum length Lmax is substantiallyequal to 20 um, and the minimum length Lmin is substantially less than20 um. Thus, when the positioning shift occurs between the firstsubstrate 60 and the second substrate 61 and the misalignment is not yetcaused between the function electrodes 60 c and the function electrodes61 c, the positioning electrode 60 a has been electrically coupled tothe positioning electrode 61 b or the positioning electrode 60 b iselectrically coupled to the positioning electrode 61 a, thereby thepositioning shift between the first substrate 60 and the secondsubstrate 61 can be known in advance. Moreover, because the distancebetween one portion of the positioning electrode 60 a and one portion ofthe positioning electrode 60 b is less than about 20 um, the short pathformed by the conductive particles of the ACF 63 can be prevented.

In the present embodiment, the positioning electrodes 60 a and 60 b aredisposed on an outer side of the first substrate 60, in other words, thepositioning electrodes 60 a and 60 b are disposed on one of the twosides of the function electrodes 60 c.

In a third embodiment of a misalignment detection device in FIG. 7 ofthe present invention, a misalignment detection device 7 comprises anintegrated circuit (IC) 70, a first substrate 71, a second substrate 72,a third substrate 73, and at least one detection unit 74. The thirdsubstrate 73 is electrically coupled to and disposed on the firstsubstrate 71 and the second substrate 72. The first substrate 71 can bea transparent substrate (such as a glass substrate, or a quartzsubstrate), an opaque substrate (such as a wafer or porcelainsubstrate), or flexible substrate (such as acrylic polymer, rubber,epoxy polymer, or ester polymer). The second substrate 72 can be aprinted circuit board (PCB), a flexible printed circuit (FPC), COF, or acombination thereof. The third substrate 73 can be a PCB, a FPC, a COF,or a combination thereof. In some embodiments, the first substrate 71 isa glass substrate, the second substrate 72 is a PCB, and the thirdsubstrate 73 is an FPC. Referring to FIG. 6A, the IC 70 comprises aplurality of bumps divided into function bumps 70 c and two adjacentpositioning bumps 70 a and 70 b. The first substrate 71 comprises aplurality of pads divided into function pads 71 c and two adjacentpositioning pads 71 a and 71 b, and the distance between any two of thefunction pads 71 c is substantially greater than the distance betweenthe positioning pads 71 a and 71 b. The first substrate 71 furthercomprises a plurality of electrodes divided into function electrodes 71f and two adjacent positioning electrodes 71 d and 71 e. The secondsubstrate 72 comprises a plurality of electrodes divided into functionelectrodes 72 c and two adjacent positioning electrodes 72 a and 72 b.The third substrate 73 comprises a plurality of electrodes on two sides.On one side of the third substrate 73, the electrodes are divided intofunction electrodes 73 c and two adjacent positioning electrodes 73 aand 73 b; and on the other side thereof, the electrodes are divided intofunction electrodes 73 f and two adjacent positioning electrodes 73 dand 73 e. In FIG. 7, because the function bumps 70 c are superimposed onthe function pads 71 c, FIG. 7 shows the function bumps 70 c on theupper level. Similarly, FIG. 7 shows the function electrodes 73 c and 73f.

ACFs are disposed between the IC 70 and first substrate 71, between thefirst substrate 71 and between the third substrate 73, and between thesecond substrate 72 and the third substrate 73, and then applying apressure on the IC 70 and first substrate 71, the first substrate 71 andthe third substrate 73, and the second substrate 72 and the thirdsubstrate 73. Between the IC 70 and first substrate 71, the functionbumps 70 c and the function pads 71 c should be aligned, and thepositioning bumps 70 a and 70 b and the positioning pads 71 a and 71 bshould be aligned in a first pressing region. Between the firstsubstrate 71 and the third substrate 73, the function electrodes 71 fand the function electrodes 73 c should be aligned, and the positioningelectrodes 71 d and 71 e and the positioning electrodes 73 a and 73 bshould be aligned in a second pressing region. Between the secondsubstrate 72 and the third substrate 73, the function electrodes 72 cand the function electrodes 73 f should be aligned, and the positioningelectrodes 72 a and 72 b and the positioning electrodes 73 d and 73 eshould be aligned in a third pressing region

In the present embodiment, between the first substrate 71 and the thirdsubstrate 73, the distance between any two of the function electrodes 71f is substantially greater than the distance between the positioningelectrodes 71 d and 71 e, or the distance between any two of thefunction electrodes 73 c is substantially greater than the distancebetween the positioning electrodes 73 a and 73 b. Between the secondsubstrate 72 and the third substrate 73, the distance between any two ofthe function electrodes 73 c is substantially greater than the distancebetween the positioning electrodes 73 d and 73 e, or the distancebetween ay two of the function electrodes 72 c is substantially greaterthan the distance between the positioning electrodes 72 a and 72 b. Inthe following description, the distance between two function electrodes71 f is substantially greater than the distance between the positioningelectrodes 71 d and 71 e, and the distance between the functionelectrodes 72 c is substantially greater than the distance between thepositioning electrodes 72 a and 72 b.

The positioning electrodes 72 a and 72 b respectively receive signalsS72 a and S72 b which have substantially different voltage levels. Whenthe misalignment detection device 7 is applied in a display device. Atleast one of the signals S72 a and S72 b disregards display devicefunctions. In other words, at least one of the signals S73 a and S73 bis not provided by the display device. For example, the signal S72 a hasthe same level as a common voltage Vcom of the display device, and thesignal S72 b has a ground level GND provided by the misalignmentdetection device 7 or an external device (not shown).

The detection unit 72 is electrically coupled to and disposed on thesecond substrate 72. The detection unit 74 detects the signals S72 a andS72 b. When positioning shift occurs in at least one among the first tothird pressing regions, the detection unit 74 outputs a fault signalS74. The display device displays incorrect images according to the faultsignal S74, and the disposition error can be detected. For example, whenthe positioning shift occurs between the IC 70 and the first substrate71 and the misalignment is thus caused between the function bumps 70 cand the function pads 71 c, the positioning bump 70 a is electricallycoupled to the positioning pad 71 b or the positioning bump 70 b iselectrically coupled to the positioning pad 71 a, at the same time, onefunction bump 70 c is electrically coupled to a function pad adjacent tothe substantially corresponding function pad 71 c. One of the signalsS72 a and S72 b is not at the original voltage level. When detectingthat the voltage level of one of the signals S72 a and S72 b is changed,the detection unit 74 outputs the fault signal S74 to indicate thepositioning shift occurs between the IC 70 and the first substrate 71.

In the present embodiment, the distance between two function pads 71 cof the first substrate 71 is substantially greater than the distancebetween the positioning pads 71 a and 71 b thereof. When the positioningshift occurs between the IC 70 and the first substrate 71, thepositioning bump 70 a has been electrically coupled to the positioningpad 71 b or the positioning bump 70 b has been electrically coupled tothe positioning pad 71 a although any one of the function bumps 70 c isnot yet electrically coupled to a function pad adjacent to thesubstantially corresponding function pad 61 c to cause the misalignment.Thus, the positioning shift can be known in advance, decreasing theprobability of the misalignment. Similarly, by the greater distancebetween two function electrodes 71 f substantially greater than thedistance between the positioning electrodes 71 d and 71 e and thegreater distance between two function electrodes 72 c substantiallygreater than the distance between the positioning electrodes 72 a and 72b, the positioning shift in the second region and/or the third pressingregion can be known in advance.

In the present embodiment, the distance between two function pads 71 cis substantially greater than the distance between the positioning pads71 a and 71 b. In some cases, although the positioning shift does notoccur between the IC 70 and the first substrate 71, the conductiveparticles of the ACF form a short path between the positioning bumps 70a and 70 b and the positioning pads 71 a and 71 b due the shorterdistance between the positioning pads 71 a and 71 b. In order to preventthe short path formed by the conductive particles of the ACF, the formsof the positioning pads 710 a and 71 b can be made as shown in FIG. 5.The distance between the positioning pads 71 a and 71 b has the maximumlength Lmax and the minimum length Lmin. It is assumed that the distancebetween two function electrodes 71 c is about 20 um, the maximum lengthLmax is substantially equal to 20 um, and the minimum length Lmin issubstantially less than 20 um. Thus, when the positioning shift occursbetween the IC 70 and the first substrate 71 and the misalignment is notyet caused between the function bumps 70 c and the function pads 71 c,the positioning bump 70 a has been electrically coupled to thepositioning pad 71 b or the positioning bump 70 b is coupled to thepositioning pad 71 a, thereby the positioning shift between the IC 70and the first substrate 71 can be known in advance. Moreover, becausethe distance between one portion of the positioning pad 71 a and oneportion of the positioning pad 71 b is less than about 20 um, the shortpath formed by the conductive particles of the ACF can be prevented.

Similarly, the forms of the positioning electrodes 71 d and 71 e of thefirst substrate 71 and the positioning electrodes 72 a and 72 b of thesecond substrate 72 can be made as shown in FIG. 5.

In present embodiment, the positioning bumps 70 a and 70 b are disposedon an outer side of the IC 70, in other words, the positioning bumps 70a and 70 b are disposed on one of the two sides of the function bumps 70c, as shown in FIG. 7. On the first substrate 71, the positioningelectrodes 71 d and 71 e are disposed on an outer side of the firstsubstrate 71, in other words, the positioning electrodes 71 d and 71 eare disposed on one of the two sides of the function electrodes 71 f.Similarly, on the second substrate 72, the positioning electrodes 72 aand 72 b are disposed on one of the two sides of the function electrodes72 c.

On the third substrate 73, the positioning electrodes 73 a and 73 b aredisposed on one of the two sides of the function electrodes 73 c, andthe positioning electrodes 73 d and 73 e are disposed on one of the twosides of the function electrodes 73 f.

The display device described above can be a liquid crystal display, anelectroluminescent display, a field-emission display, a nano-carbon tubedisplay, or other display. An electroluminescent display has organic(small molecules or macromolecules) or inorganic types. In the aboveembodiments of the present invention, a liquid crystal display is givenas an exemplary display device.

While the present invention has been described by way of example and interms of the preferred embodiments, it is to be understood that thepresent invention is not limited to the disclosed embodiments. To thecontrary, it is intended to cover various modifications and similararrangements (as would be apparent to those skilled in the art).Therefore, the scope of the appended claims should be accorded thebroadest interpretation so as to encompass all such modifications andsimilar arrangements.

What is claimed is:
 1. A misalignment detection device comprising: afirst substrate comprising a first positioning electrode and a secondpositioning electrode adjacent to the first positioning electrode; asecond substrate comprising a third positioning electrode and a fourthpositioning electrode adjacent to the third positioning electrode,wherein the third positioning electrode and the fourth positioningelectrode substantially correspond to the first positioning electrodeand the second positioning electrode, respectively; and at least onedetection unit electrically coupled to the first substrate, wherein theat least one detection unit outputs a fault signal in response to apositioning shift occurring between the first and second positioningelectrodes and the third and fourth positioning electrodes; wherein thefirst positioning electrode comprises a first portion and a secondportion whose area is smaller than the area of the first portion, andthe second positioning electrode comprises a third portion and a fourthportion whose area is smaller than the third portion; and wherein thesecond portion and the fourth portion are disposed between the firstportion and the third portion.
 2. The device of claim 1, wherein thefirst positioning electrode is adapted to receive a first signal, thesecond positioning electrode is adapted to receive a second signal, andthe at least one detection unit detects that a level of the first orsecond signal changes as a result of the positioning shift.
 3. Thedevice of claim 1, wherein the first substrate comprises a plurality offirst function electrodes, the second substrate comprises a plurality ofsecond function electrodes, and each second function electrodesubstantially corresponds to the each first function electrode.
 4. Thedevice of claim 3, wherein a distance between any two of the firstfunction electrodes is substantially greater than a distance between thefirst positioning electrode and the second positioning electrode.
 5. Thedevice of claim 3, wherein a distance between any two of the secondfunction electrodes is substantially greater than a distance between thethird positioning electrode and the fourth positioning electrode.
 6. Thedevice of claim 4, wherein the first and second positioning electrodesare disposed on an outer side of the first substrate.
 7. A misalignmentdetection device comprising: a first substrate comprising a firstpositioning electrode, a second positioning electrode adjacent to thefirst positioning electrode, and a plurality of first functionelectrodes a second substrate comprising a third positioning electrode,a fourth positioning electrode adjacent to the third positioningelectrode, and a plurality of second function electrodes, wherein thethird positioning electrode and the fourth positioning electrodesubstantially correspond to the first positioning electrode and thesecond positioning electrode, respectively, and each second functionelectrode substantially corresponds to the each first functionelectrode; and at least one detection unit electrically coupled to thefirst substrate, wherein the at least one detection unit outputs a faultsignal in response to a positioning shift occurring between the firstand second positioning electrodes and the third and fourth positioningelectrodes; wherein a width of the first positioning electrode and awidth of the second positioning electrode are larger than widths of thefirst function electrodes, and wherein a distance between the firstpositioning electrode and the second positioning electrode is less thana distance between two adjacent function electrodes among the firstfunction electrodes.
 8. The device of claim 7, wherein the firstpositioning electrode is adapted to receive a first signal, the secondpositioning electrode is adapted to receive a second signal, and the atleast one detection unit detects that a level of the first or secondsignal changes as a result of the positioning shift.
 9. The device ofclaim 8, wherein a distance between any two of the first functionelectrodes is substantially greater than a distance between the firstpositioning electrode and the second positioning electrode.
 10. Thedevice of claim 8, wherein a distance between any two of the secondfunction electrodes is substantially greater than a distance between thethird positioning electrode and the fourth positioning electrode. 11.The device of claim 7, wherein the first and second positioningelectrodes are disposed an outer side of the first substrate.
 12. Thedevice of claim 7, wherein the first and second positioning electrodesare not located between any two of the function electrodes.
 13. Thedevice of claim 7, wherein one of the first and second substratecomprises a circuit board or flexible circuit board.
 14. The device ofclaim 7, wherein the first positioning electrode comprises a firstportion and a second portion whose area is smaller than the area of thefirst portion, and the second positioning electrode comprises a thirdportion and a fourth portion whose area is smaller than the thirdportion; and wherein the second portion and the fourth portion aredisposed between the first portion and the third portion.